U.S. patent application number 10/550209 was filed with the patent office on 2006-09-14 for polymer and polymer light-emitting device using same.
This patent application is currently assigned to SUMITOMO CHEMICAL COMPANY, LIMITED. Invention is credited to Hideaki Nakajima, Akihiko Okada, Tomoyuki Suziki.
Application Number | 20060204782 10/550209 |
Document ID | / |
Family ID | 33127379 |
Filed Date | 2006-09-14 |
United States Patent
Application |
20060204782 |
Kind Code |
A1 |
Okada; Akihiko ; et
al. |
September 14, 2006 |
Polymer and polymer light-emitting device using same
Abstract
A polymer emitting fluorescence in the solid state, having a
polystyrene-reduced weight-average molecular weight of 10.sup.3 to
10.sup.8 and having a repeating unit selected from the group
consisting of arylene group, divalent heterocyclic group and
divalent aromatic amine group, wherein the polymer has an
unsaturated hydrocarbon group free of aromatic ring which directly
bonds to any one of the repeating units, at least, at one terminal
end of the main chain thereof.
Inventors: |
Okada; Akihiko;
(Tsukuba-shi, JP) ; Suziki; Tomoyuki;
(Tsukuba-shi, JP) ; Nakajima; Hideaki;
(Tsukuba-shi, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
SUMITOMO CHEMICAL COMPANY,
LIMITED
27-1, Shinkawa 2-Chome Chuo-Ku
Tokyo
JP
|
Family ID: |
33127379 |
Appl. No.: |
10/550209 |
Filed: |
March 29, 2004 |
PCT Filed: |
March 29, 2004 |
PCT NO: |
PCT/JP04/04431 |
371 Date: |
September 21, 2005 |
Current U.S.
Class: |
428/690 |
Current CPC
Class: |
H01L 51/0036 20130101;
H01L 51/0094 20130101; H01L 51/5012 20130101; C08G 61/00 20130101;
H05B 33/14 20130101; C09K 11/06 20130101; C09K 2211/14
20130101 |
Class at
Publication: |
428/690 |
International
Class: |
B32B 19/00 20060101
B32B019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2003 |
JP |
2003-094088 |
Claims
1. A polymer emitting fluorescence in the solid state, having a
polystyrene-reduced weight-average molecular weight of 10.sup.3 to
10.sup.8 and having a repeating unit selected from the group
consisting of arylene group, divalent heterocyclic group and
divalent aromatic amine group, wherein the polymer has an
unsaturated hydrocarbon group free of aromatic ring at least at one
terminal end of the main chain thereof with being directly coupled
with any of the repeating units.
2. A polymer according to claim 1, wherein the unsaturated
hydrocarbon group free of aromatic ring is a group represented by
formula (2) and being free of aromatic ring:
C.sub.iH.sub.2(i-j)-1-- (2) wherein, i is an integer of 5 or more,
and j is an integer satisfying the range of 0.ltoreq.j<i/2.
3. A polymer according to claim 2, wherein i is 8 and j is any one
of 0, 1 or 2 in formula (2).
4. A polymer according to claim 1, wherein the unsaturated
hydrocarbon group free of aromatic ring is cyclooctadienyl
group.
5. A method for producing the polymer according to claim 4, wherein
at least one monomer selected from the group consisting of the
following formula (3), (4) and (5) is subjected to reaction with a
compound represented by the following formula (6):
Y.sub.1--Ar.sub.1--Y.sub.2 (3); Y.sub.3--Ar.sub.2--Y.sub.4 (4);
Y.sub.5--Ar.sub.3--Y.sub.6 (5); and E.sub.1-Y.sub.7 (6); wherein
Ar.sub.1, Ar.sub.2 and Ar.sub.3 each independently represents
arylene group, divalent heterocyclic group and divalent aromatic
amine group; E.sub.1 represents an unsaturated hydrocarbon group
free of aromatic ring; Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5
and Y.sub.6 each independently represents a leaving group; and
Y.sub.7 represents a hydrogen atom or a leaving group.
6. A method for producing the polymer according to claim 5, wherein
a monomer of which Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and
Y.sub.6 is each independently a halogen atom, an alkylsulfonyloxy
group or an arylsulfonyloxy group, and Y.sub.7 is a hydrogen atom,
a halogen atom, an alkylsulfonyloxy group or an arylsulfonyloxy
group, is subjected to reaction in the presence of Ni(0)
complex.
7. A method for producing the polymer according to claim 5, wherein
Y.sub.7 is hydrogen atom and E.sub.1 is a group containing two or
more unsaturated bonds.
8. A method for producing the polymer according to claim 7, wherein
a compound represented by formula (6) is cyclooctadiene and an
amount of the cyclooctadiene is 100 to 300% by mole based on the
total amount of monomers represented by formulas (3), (4) and
(5).
9. A polymer produced by the method according to claim 5.
10. A polymer composition comprising a polymer having a
polystyrene-reduced number-average molecular weight of 10.sup.3 to
10.sup.8 and emitting fluorescence in the solid state, and the
polymer according to claim 1.
11. A polymer composition comprising two or more polymers according
to claim 1.
12. A polymer light emitting device comprising a light emitting
layer disposed between an anode electrode and a cathode electrode,
wherein the light emitting layer comprises a polymer emitting
fluorescence in the solid state, the polymer having a
polystyrene-reduced weight-average molecular weight of 10.sup.3 to
10.sup.8 and having a repeating unit selected from the group
consisting of arylene group, divalent heterocyclic group and
divalent aromatic amine group, wherein the polymer has an
unsaturated hydrocarbon group free of aromatic ring at least at one
terminal end of the main chain thereof with being directly coupled
with any of the repeating units or a polymer composition comprising
a polymer having a polystyrene-reduced number-average molecular
weight of 10.sup.3 to 10.sup.8 and emitting fluorescence in the
solid state.
13. A flat light source comprising the polymer light emitting
device according to claim 12.
14. A segment display comprising the polymer light emitting device
according to claim 12.
15. A dot matrix display comprising the polymer light emitting
device according to claim 12.
16. A liquid crystal display comprising a backlight composed of the
polymer light emitting device according to claim 12.
Description
TECHNICAL FIELD
[0001] The invention relates to a polymer and a polymer light
emitting device using the same (hereafter, referred to as a polymer
LED).
BACKGROUND ART
[0002] Since light emitting substances having high molecular weight
are different from those having low molecular weight in terms of
being soluble in solvents and being able to form a light emitting
layer for light emitting device by coating methods, various types
of them have been studied; known as one of examples is a polymer
whose main chain has a repeating unit containing aromatic ring and
a phenyl group at the terminal end thereof (WO01/49769).
[0003] Where, for example, a polymer is used as a light emitting
substance for a light emitting device, the polymer has to be
resistible to electrolytic oxidation and/or reduction, particularly
to electrolytic reduction which seems to be frequently caused by
the electric current supplied to a light emitting device.
[0004] The above polymer, however, has disadvantage of insufficient
resistibility to electrolytic reduction.
DISCLOSURE OF THE INVENTION
[0005] The object of the invention is to provide a polymer which is
resistible to electrolytic oxidation and/or reduction, particularly
to electrolytic reduction.
[0006] The inventors of the invention have diligently studied to
solve the above problems, found that a polymer having a terminal
end group of unsaturated hydrocarbon group free of aromatic ring at
least at one terminal end thereof is resistible to electrolytic
reduction, and achieved the invention.
[0007] Namely, the invention provides a polymer emitting
fluorescence in the solid state, having a polystyrene-reduced
weight-average molecular weight of 10.sup.3 to 10.sup.8 and having
a repeating unit selected from the group consisting of arylene
group, divalent heterocyclic group and divalent aromatic amine
group, wherein the polymer has an unsaturated hydrocarbon group
free of aromatic ring at least at one terminal end of the main
chain thereof with being directly coupled with any of the repeating
units. The term of "emitting fluorescence" defines that a compound
emits light through excited "singlet" state when the compound is
excited by absorption of excitation energy such as light or
electric energy.
BEST MODE FOR CARRYING OUT THE INVENTION
[0008] The polymer of the invention has an unsaturated hydrocarbon
group free of aromatic ring at least at one terminal end of the
main chain thereof with being directly coupled with any of the
repeating units thereof. To say another word, the polymer of the
invention has at terminal ends thereof a structure represented by
the following formula (1): -A-E (1) wherein A represents any of the
repeating units included in the polymer and E represents an
unsaturated hydrocarbon group free of aromatic ring.
[0009] The number of carbon atoms of the unsaturated hydrocarbon
group free of aromatic ring which is included in the polymer of the
invention, is usually about 3 to 20, and preferably 4 to 12. The
term of unsaturated bond defines a double bond or a triple
bond.
[0010] The unsaturated hydrocarbon group free of aromatic ring
includes, for example, an acyclic hydrocarbon group containing
unsaturated bond and being optionally substituted by alicyclic
hydrocarbon group; and an alicyclic hydrocarbon group containing
unsaturated bond and being optionally substituted by acyclic
hydrocarbon group.
[0011] As the unsaturated hydrocarbon group free of aromatic ring,
following groups are exemplified. ##STR1## ##STR2## ##STR3##
##STR4## ##STR5## ##STR6## ##STR7## ##STR8## ##STR9## ##STR10##
##STR11## ##STR12## ##STR13## ##STR14## ##STR15## ##STR16##
##STR17## ##STR18## ##STR19## ##STR20## ##STR21## ##STR22##
##STR23## ##STR24## ##STR25## ##STR26## ##STR27## ##STR28##
##STR29## ##STR30## ##STR31## ##STR32## ##STR33## ##STR34##
##STR35## ##STR36## ##STR37## ##STR38## ##STR39## ##STR40##
##STR41## ##STR42## ##STR43## ##STR44## ##STR45## ##STR46##
##STR47## ##STR48## ##STR49## ##STR50## ##STR51## ##STR52##
##STR53## ##STR54## ##STR55## ##STR56##
[0012] In the above formula, * represents a bonding part to main
chain.
[0013] It is preferable that the unsaturated hydrocarbon group free
of aromatic ring does not contain a methyl group.
[0014] Namely, in the above examples, followings are more
preferable. E002, E039, E045, E046, E048, E049, E056, E060, E067,
E076, E077, E078, E079, E080, E081, E086, E089, E091, E092, E093,
E109, E113, E116, E118, E119, E136, E137, E138, E139, E140, E141,
E142, E143, E144, E145, E146, E147, E148, E149, E150, E151, E158,
E165, E172, E179, E180, E181, E182, E183, E190, E194, E195, E196,
E197, E198, E228, E229, E230, E231, E232, E233, E234, E235, E236,
E237, E244, E250, E251, E252, E253, E254, E255, E256, E262, E267,
E274, E282, E295, E323, E355, E383, E422, E423, E424, E425, E426,
E427, E428, E429, E430, E431, E432, E433, E434, E435, E436, E442,
E448, E449, E450, E451, E452, E453, E454, E455, E456, E457, E458,
E459, E460, E461, E462, E463, E464, E465, E466, E467, E468, E469,
E470, E477, E478, E479, E480, E484, E491, E492, E493, E494, E504,
E508, E509, E515, E516, E517, E518, E519, E520, E521, E522, E523,
E524, E525, E526, E527, E530, E535, E539, E540, E541, and E548 are
preferable, and E136, E137, E142, E143, E144, E145, E146, E147,
E148, E149, and E150.
[0015] It is preferable that the unsaturated hydrocarbon group free
of aromatic ring is a group represented by the following formula
(2) and being free of aromatic ring: C.sub.iH.sub.2(i-j)-1-- (2)
wherein i is an integer of 5 or more, and j is an integer
satisfying the range of 0 j<i/2. The i is usually 20 or
less.
[0016] It is preferable that the i is 8 and the j is any one of 0,
1 or 2 in formula (2), or more preferable is cyclooctadienyl
group.
[0017] Of the unsaturated hydrocarbon group free of aromatic ring,
a group derived from cycloalkadiene is preferable. That the polymer
has cycloalkadiene-derived group at least at one terminal end of
its molecular chain means a state that polymerization reaction is
carried out by addition of cycloalkadiene or a compound of
cycloalkadiene having a leaving group, followed by the
cycloalkadiene portion of the compound being coupled with at least
at one end of the repeating unit of the polymer.
[0018] When 1,5-cyclooctadiene is used as an example of
cycloalkadiene, following cases are exemplified: a structure in
which a monovalent hydrocarbon group derived from
1,5-cyclooctadiene after leaving one hydrogen atom therefrom is
replaced with a leaving group of the monomers used for
polymerization; a structure in which a divalent hydrocarbon group
resulting from 1,5-cyclooctadiene after one of double bonds thereof
being opened is coupled at its one end with hydrogen atom and
replaced at its another end with a leaving group of the monomers
used for polymerization, or an isomeric structure thereof having
different bonding site with the repeating units of the polymer; or
a structure in which one more double bond is increased after the
ring thereof being broken, or an isomeric structure thereof.
[0019] Of the polymer of the invention, at least one terminal end
of molecular chain thereof is an unsaturated hydrocarbon group free
of aromatic ring. The unsaturated hydrocarbon group free of
aromatic ring may be one kind, two kinds or more. It is preferable
for the polymer of the invention that the content of a polymer
having at both ends thereof the unsaturated hydrocarbon groups free
of aromatic ring is more than that of a polymer having at only one
end thereof the unsaturated hydrocarbon group free of aromatic
ring; or more preferably that the content of a polymer having at
both ends thereof the unsaturated hydrocarbon groups free of
aromatic ring is equal to or more than two times of that of a
polymer having at only one end thereof the unsaturated hydrocarbon
group free of aromatic ring.
[0020] Of the terminal ends of the polymer of the invention, a
terminal end other than the unsaturated hydrocarbon group free of
aromatic ring is preferably a terminal end group derived from
monomers used for polymerization of which one of leaving groups is
substituted by hydrogen atom (referred to as a hydrogen-substituted
terminal end group hereinafter). The content of terminal end groups
other than the unsaturated hydrocarbon group free of aromatic ring
and the hydrogen-substituted terminal end group is preferably 30%
or less based on that of total terminal ends, more preferably 20%
or less, still more preferably 10% or less, or most preferably not
being existed.
[0021] When, for example, the polymer of the invention is produced
by using a monomer having halogen atom as a raw material therefor,
since halogen atom remained at the polymer terminal end tends to
degrade fluorescence property and the like, it is preferable that
halogen atom is substantially not remained at the terminal
ends.
[0022] A ratio of a polymer coupled with a terminal end group to
the whole polymers can be calculated by comparing intensities of
mass spectrum obtained by a Matrix Assisted Laser Desorption
Ionization Time-of-flight Mass Spectrometry. For example, when,
over the whole range of mass number peaks of the polymer detected
in the mass spectrum, an intensity of mass number peak of a polymer
having at both ends thereof aliphatic hydrocarbon group containing
unsaturated bond is greater than that of a polymer having at only
one end thereof aliphatic hydrocarbon group containing unsaturated
bond, the content of the polymer having at both ends thereof
aliphatic hydrocarbon group containing unsaturated bond is deemed
to be grater than that of the polymer having at only one end
thereof aliphatic hydrocarbon group containing unsaturated
bond.
[0023] The polymer of the present invention has one or more kinds
of repeating units selected from the group consisting of an arylene
group, a divalent heterocyclic group, and divalent aromatic amine
group.
[0024] Here, the arylene group means an atomic group in which two
hydrogen atoms are removed from an aromatic hydrocarbon, and
includes those containing two or more of independent benzene rings
or condensed rings bonded through a group such as a direct bond, a
vinylene group or the like.
[0025] The number of carbon atoms constituting the ring of the
arylene group is usually about 6 to 60. As the arylene groups,
specifically exemplified are: phenylene group, fluorenediyl group,
biphenylene group, terphenylene group, naphthalenediyl group,
anthracenediyl group, phenanthrene diyl group, pentalenediyl group,
indenediyl group, heptalenediyl group, indacenediyl group,
triphenylenediyl group, binaphthyldiyl group, phenylnaphthylenediyl
group, stilbenediyl group, 3,3'-alkoxystilbenediyl group, etc.; and
preferably, phenylene group and fluorenediyl group.
[0026] As the phenylene group, for example, following groups are
exemplified. ##STR57##
[0027] As the fluorenediyl group, for example, following groups are
exemplified. ##STR58## ##STR59##
[0028] Here, as R, a hydrogen atom, alkyl group, alkoxy group,
alkylthio group, alkylsilyl group, alkylamino group, hydroxyl
group, amino group, carboxyl group, aldehyde group, cyano group,
etc. are exemplified; and alkyl group, alkoxy group, hydroxyl
group, amino group, carboxyl group, and aldehyde group are
preferable.
[0029] In the above formula, a plurality of Rs are contained in one
group, they may be the same or different with each other.
[0030] The alkyl group may be any of linear, branched or cyclic,
and usually has about 1 to 20 carbon atoms, and specific examples
thereof include methyl group, ethyl group, propyl group, i-propyl
group, butyl group, i-butyl group, t-butyl group, pentyl group,
isoamyl group, hexyl group, cyclohexyl group, heptyl group, octyl
group, 2-ethylhexyl group, nonyl group, decyl group,
3,7-dimethyloctyl group, lauryl group, etc.
[0031] The alkoxyl group may be any of linear, branched or cyclic,
and usually has about 1 to 20 carbon atoms, and specific examples
thereof include methoxy group, ethoxy group, propyloxy group,
i-propyloxy group, butoxy group, i-butoxy group, t-butoxy group,
pentyloxy group, isoamyl oxy group, hexyloxy group, cyclohexyloxy
group, heptyloxy group, octyloxy group, 2-ethylhexyloxy group,
nonyloxy group, decyloxy group, 3,7-dimethyloctyloxy group,
lauryloxy group, etc.
[0032] The alkylthio group may be any of linear, branched or
cyclic, and usually has about 1 to 20 carbon atoms, and specific
examples thereof include methylthio group, ethylthio group,
propylthio group, i-propylthio group, butylthio group, i-butylthio
group, t-butylthio group, pentylthio group, hexylthio group,
cyclohexylthio group, heptylthio group, octylthio group,
2-ethylhexylthio group, nonylthio group, decylthio group,
3,7-dimethyloctylthio group, laurylthio group, etc.
[0033] The alkylsilyl group may be any of linear, branched or
cyclic, and usually has about 1 to 60 carbon atoms, and specific
examples thereof include methylsilyl group, ethylsilyl group,
propylsilyl group, i-propylsilyl group, butylsilyl group,
i-butylsilyl group, t-butylsilyl group, pentylsilyl group,
hexylsilyl group, cyclohexylsilyl group, heptylsilyl group,
octylsilyl group, 2-ethylhexylsilyl group, nonylsilyl group,
decylsilyl group, 3,7-dimethyloctylsilyl group, laurylsilyl group,
trimethylsilyl group, ethyldimethylsilyl group, propyldimethylsilyl
group, i-propyldimethylsilyl group, butyldimethylsilyl group,
t-butyldimethylsilyl group, pentyldimethylsilyl group,
hexyldimethylsilyl group, heptyldimethylsilyl group,
octyldimethylsilyl group, 2-ethyl hexyl-dimethylsilyl group,
nonyldimethylsilyl group, decyldimethylsilyl group,
3,7-dimethyloctyl-dimethylsilyl group, lauryldimethylsilyl group,
etc.
[0034] The alkylamino group may be any of linear, branched or
cyclic, and may be either monoalkylamino group or dialkylamino
group. The number of carbon atoms are usually about 1 to 40, and
specific examples thereof include methylamino group, dimethyl amino
group, ethylamino group, diethylamino group, propylamino group,
i-propylamino group, butylamino group, and i-butylamino group,
t-butylamino group, pentylamino group, hexylamino group,
cyclohexylamino group, heptylamino group, octylamino group,
2-ethylhexylamino group, nonylamino group, decylamino group,
3,7-dimethyloctylamino group, laurylamino group, etc.
[0035] The divalent heterocyclic group means an atomic group in
which two hydrogen atoms are removed from a heterocyclic compound,
and the number of carbon atoms which constitutes a ring is usually
about 4 to 60.
[0036] Examples of the divalent heterocyclic group include: 6
membered heterocyclic groups containing a hetero atom, groups
having fluorene structure containing a hetero atom, 5 membered
heterocyclic groups containing a hetero atom, condensed
heterocyclic groups having 5- or 6-membered heterocyclic groups
containing a hetero atom; 5 membered heterocyclic groups containing
a hetero atom, which are connected at the a position of the hetero
atom to form a dimer or an oligomer; 5 membered heterocyclic groups
containing a hetero atom, which are connected with a phenyl group
at the a position of the hetero atom, etc.
[0037] As the hetero atom, nitrogen, oxygen, sulfur, silicon, and
selenium are exemplified and nitrogen, oxygen, and sulfur are
preferable. In the case of 6 membered-ring heterocyclic group
containing a hetero atom, it is preferable that a hetero atom is
nitrogen.
[0038] As the 6 membered heterocyclic groups containing a hetero
atom, for example, following groups are exemplified. ##STR60##
[0039] As the groups having fluorene structure containing a hetero
atom, for example, following groups are exemplified. ##STR61##
##STR62##
[0040] As the 5 membered heterocyclic groups containing a hetero
atom, for example, following groups are exemplified. ##STR63##
[0041] As the condensed heterocyclic groups having 5- or 6-membered
heterocyclic groups containing a hetero atom, for example,
following groups are exemplified. ##STR64## ##STR65## ##STR66##
[0042] As the 5 membered heterocyclic groups containing a hetero
atom, which are connected at the a position of the hetero atom to
form a dimer or an oligomer, for example, following groups are
exemplified. ##STR67##
[0043] As the 5 membered heterocyclic groups containing a hetero
atom, which are connected with a phenyl group at the a position of
the hetero atom, for example, following groups are exemplified.
##STR68##
[0044] Here, as R, a hydrogen atom, alkyl group, alkoxy group,
alkylthio group, alkylsilyl group, alkylamino group, hydroxyl
group, amino group, carboxyl group, aldehyde group, cyano group,
etc. are exemplified.
[0045] In the above formula, a plurality of Rs are contained in one
group, but they may be the same or different from each other.
[0046] As for the alkyl group, alkoxy group, alkylthio group,
alkylsilyl group, and alkylamino group, the above structures are
exemplified
[0047] The divalent aromatic amine group means an atomic group in
which two hydrogen atoms are removed from the aromatic ring of
aromatic amine.
[0048] As the divalent aromatic amine group, for example, groups
represented by formula-(7) are exemplified. ##STR69##
[0049] Wherein, Ar.sub.1, Ar.sub.3 and Ar.sub.5 are each
independently an arylene group or a divalent heterocyclic group.
Ar.sub.2 and Ar.sub.4 are each independently an aryl group or a
monovalent heterocyclic group. n represents an integer of 0-3. When
n is two or more, a plurality of Ar.sub.4 and Ar.sub.5 may be the
same or different.
[0050] Ar.sub.1, Ar.sub.2, Ar.sub.3, Ar.sub.4 and Ar.sub.5 in the
repeating unit represented by the above formula (7) may have a
substituent, such as alkyl group, alkoxy group, alkylthio group,
alkylsilyl group, alkylamino group, aryl group, aryloxy group, aryl
silyl group, etc.
[0051] The definition and the concrete examples of alkyl group,
alkoxy group, alkylthio group, alkylsilyl group, alkylamino group,
and aryl group are the same with those definitions and the concrete
examples in the above R.
[0052] The aryloxy group usually has about 6 to 60 carbon atoms,
and specific examples thereof include phenoxy group,
C.sub.1-C.sub.12 alkoxyphenoxy group, C.sub.1-C.sub.12 alkylphenoxy
group, 1-naphtyloxy group, 2-naphtyloxy group, etc., and
C.sub.1-C.sub.12 alkoxyphenoxy group, and C.sub.1-C.sub.12
alkylphenoxy group are preferable.
[0053] The aryl silyl group usually has about 6 to 60 carbon atoms,
and specific examples thereof include phenyl silyl group,
C.sub.1-C.sub.12 alkoxyphenyl silyl group, C.sub.1-C.sub.12
alkylphenyl silyl group, 1-naphtyl silyl group, 2-naphtyl silyl
group, dimethylphenyl silyl group, etc., and C.sub.1-C.sub.12
alkoxyphenyl silyl group and C.sub.1-C.sub.12 alkylphenyl silyl
group are preferable.
[0054] The aryl amino group usually has about 6 to 60 carbon atoms,
and specific examples thereof include phenyl amino group, diphenyl
amino group, C.sub.1-C.sub.12 alkoxyphenyl amino group,
di(C.sub.1-C.sub.12 alkoxyphenyl)amino group, di(C.sub.1-C.sub.12
alkyl phenyl)amino group, 1-naphtyl amino group, 2-naphtyl amino
group, etc., and C.sub.1-C.sub.12 alkylphenyl amino group and
di(C.sub.1-C.sub.12 alkylphenyl)amino group are preferable.
[0055] The arylalkyl group usually has about 7 to 60 carbon atoms,
and specific examples thereof include phenyl-C.sub.1-C.sub.12 alkyl
group, C.sub.1-C.sub.12 alkoxyphenyl-C.sub.1-C.sub.12 alkyl group,
C.sub.1-C.sub.12 alkylphenyl-C.sub.1-C.sub.12 alkyl group,
1-naphtyl-C.sub.1-C.sub.12 alkyl group, 2-naphtyl-C.sub.1-C.sub.12
alkyl group, etc., and C.sub.1-C.sub.12
alkoxyphenyl-C.sub.1-C.sub.12 alkyl group, and C.sub.1-C.sub.12
alkylphenyl-C.sub.1-C.sub.12 alkyl group are preferable.
[0056] The arylalkoxy group usually has about 7 to 60 carbon atoms,
and specific examples thereof include phenyl-C.sub.1-C.sub.12
alkoxy group, C.sub.1-C.sub.12 alkoxyphenyl-C.sub.1-C.sub.12 alkoxy
group, C.sub.1-C.sub.12 alkylphenyl-C.sub.1-C.sub.12 alkoxy group,
1-naphtyl-C.sub.1-C.sub.12 alkoxy group, 2-naphtyl-C.sub.1-C.sub.12
alkoxy group, etc., and C.sub.1-C.sub.12
alkoxyphenyl-C.sub.1-C.sub.12 alkoxy group, and C.sub.1-C.sub.12
alkylphenyl-C.sub.1-C.sub.12 alkoxy group are preferable.
[0057] The aryl alkylsilyl group usually has about 7 to 60 carbon
atoms, and specific examples thereof include
phenyl-C.sub.1-C.sub.12 alkylsilyl group, C.sub.1-C.sub.12
alkoxyphenyl-C.sub.1-C.sub.12 alkylsilyl group, C.sub.1-C.sub.12
alkylphenyl-C.sub.1-C.sub.12 alkylsilyl group,
1-naphtyl-C.sub.1-C.sub.12 alkylsilyl group,
2-naphtyl-C.sub.1-C.sub.12 alkylsilyl group,
phenyl-C.sub.1-C.sub.12 alkyldimethyl silyl group, etc., and
C.sub.1-C.sub.12 alkoxyphenyl-C.sub.1-C.sub.12 alkylsilyl group,
and C.sub.1-C.sub.12 alkylphenyl-C.sub.1-C.sub.12 alkylsilyl group
are preferable.
[0058] The arylalkylamino group usually has about 7 to 60 carbon
atoms, and specific examples thereof include
phenyl-C.sub.1-C.sub.12 alkylamino group, C.sub.1-C.sub.12
alkoxyphenyl-C.sub.1-C.sub.12 alkylamino group, C.sub.1-C.sub.12
alkylphenyl-C.sub.1-C.sub.12 alkylamino group, di(C.sub.1-C.sub.12
alkoxyphenyl-C.sub.1-C.sub.12 alkyl)amino group,
di(C.sub.1-C.sub.12 alkylphenyl-C.sub.1-C.sub.12 alkyl)amino group,
1-naphtyl-C.sub.1-C.sub.12 alkylamino group,
2-naphtyl-C.sub.1-C.sub.12 alkylamino group, etc.; and
C.sub.1-C.sub.12 alkylphenyl-C.sub.1-C.sub.12 alkylamino group, and
diC.sub.1-C.sub.12 alkylphenyl-C.sub.1-C.sub.12 alkyl)amino group
are preferable.
[0059] The arylalkenyl group usually has about 8 to 60 carbon
atoms, and specific examples thereof include
phenyl-C.sub.2-C.sub.12 alkenyl group, C.sub.1-C.sub.12
alkoxyphenyl-C.sub.2-C.sub.12 alkenyl group, C.sub.1-C.sub.12
alkylphenyl-C.sub.2-C.sub.12 alkenyl group,
1-naphtyl-C.sub.2-C.sub.12 alkenyl group,
2-naphtyl-C.sub.2-C.sub.12 alkenyl group, etc.; and
C.sub.1-C.sub.12 alkoxyphenyl-C.sub.2-C.sub.12 alkenyl group, and
C.sub.1-C.sub.12 alkylphenyl-C.sub.2-C.sub.12 alkenyl group are
preferable.
[0060] The arylalkynyl group usually has about 7 to 60 carbon
atoms, and specific examples thereof include
phenyl-C.sub.2-C.sub.12 alkynyl group, C.sub.1-C.sub.12
alkoxyphenyl-C.sub.1-C.sub.12 alkynyl group, C.sub.1-C.sub.12
alkylphenyl-C.sub.2-C.sub.12 alkynyl group,
1-naphtyl-C.sub.2-C.sub.12 alkynyl group,
2-naphtyl-C.sub.2-C.sub.12 alkynyl group, etc.; and
C.sub.1-C.sub.12 alkoxyphenyl-C.sub.2-C.sub.12 alkynyl group, and
C.sub.1-C.sub.12 alkyl phenyl-C.sub.2-C.sub.12 alkynyl group are
preferable.
[0061] Specific Examples of the repeating unit represented by the
above formula (7), those represented by the below formulae are
exemplified. ##STR70## ##STR71##
[0062] As R, a hydrogen atom, alkyl group, alkoxy group, alkylthio
group, alkylsilyl group, alkylamino group, hydroxyl group, amino
group, carboxyl group, aldehyde group, cyano group, etc. are
exemplified; and alkyl group, alkoxy group, hydroxyl group, amino
group, carboxyl group, and aldehyde group are preferable.
[0063] In the above formulae, a plurality of Rs are contained in
one group, but they may be the same or different with each
other.
[0064] The polymer of the invention has a repeating unit selected
from the group consisting of arylene group, divalent heterocyclic
group and divalent aromatic amine group.
[0065] In view of polymer characteristics such as solubility and
fluorescence intensity, the polymer of the invention is preferably
a polymer including one kind of arylene group as the repeating unit
thereof, a copolymer including two kinds of arylene group as the
repeating unit thereof, a copolymer including two kinds of divalent
heterocyclic groups as the repeating unit thereof, a copolymer
including two kinds of divalent aromatic amine groups as the
repeating unit thereof, a copolymer including one kind of arylene
group and one kind of divalent aromatic amine group as the
repeating units thereof, a copolymer including one kind of arylene
group and two kinds of divalent aromatic amine groups as the
repeating unit thereof, a copolymer including one kind of divalent
heterocyclic group and one kind of divalent aromatic amine group as
the repeating unit thereof, and a copolymer including one kind of
divalent heterocyclic group and two kinds of divalent aromatic
amine groups as the repeating unit thereof; more preferably a
polymer including one kind of arylene group as the repeating unit
thereof, a copolymer including two kinds of arylene group as the
repeating unit thereof, a copolymer including one kind of arylene
group and two kinds of divalent aromatic amine groups as the
repeating unit thereof, a copolymer including one kind of divalent
heterocyclic group and one kind of divalent aromatic amine group as
the repeating unit thereof, and a copolymer including one kind of
divalent heterocyclic group and two kinds of divalent aromatic
amine groups as the repeating units thereof; or still more
preferably a copolymer including two kinds of arylene group as the
repeating unit thereof, a copolymer including one kind of divalent
heterocyclic group and one kind of divalent aromatic amine group as
the repeating unit thereof, and a copolymer including one kind of
divalent heterocyclic group and two kinds of divalent aromatic
amine groups as the repeating unit thereof.
[0066] The polymer of the invention may, as long as its
characteristics such as fluorescence property and charge
tansporting property are not damaged, include repeating units other
than the repeating unit selected from the group consisting of
arylene group, divalent heterocyclic group and divalent aromatic
amine group.
[0067] The polystyrene-reduced weight-average molecular weight of
the polymer of the invention is usually 10.sup.3 to 10.sup.8,
preferably, from a point of view about film forming property,
1.times.10.sup.4 to 5.times.10.sup.6, more preferably
1.times.10.sup.5 to 2.times.10.sup.6, still more preferably
2.times.10.sup.5 to 1.times.10.sup.6, or particularly preferably
3.times.10.sup.5 to 1.times.10.sup.6.
[0068] The good solvent for the polymer of the invention include
chloroform, methylene chloride, dichloroethane, tetrahydrofuran,
toluene, xylene, mesitylene, decalin and n-butylbenzene. The
polymer may be dissolved in such solvent in an amount of 0.1% by
weight or more depending on a structure or molecular weight
thereof. The polymer of the invention is excellent in resistibility
to electrolytic oxidation and/or reduction. The resistibility of
the polymer to electrolytic reduction may, for example, be
evaluated according to the molecular weight change thereof while a
thin film thereof is retained with being used with negative
voltage. The negative voltage may be used by a conventional way, as
being mentioned later, such that an electrode coated with a polymer
is employed as a working electrode in a Cyclic Voltammetry. A
molecular weight change may be obtained by a gel permeation
chromatography. Employing a ratio of molecular weight change for
evaluating the molecular weight change is preferable to avoid
effect caused by the extent of the average molecular weight of the
polymer before voltage application; the ratio is defined by that
the difference between average molecular weights of a polymer
before and after voltage application is divided by the average
molecular weight of the polymer before voltage application.
[0069] The resistibility of the polymer to electrolytic oxidation
may, for example, be evaluated according to the molecular weight
change thereof while a thin film thereof is retained with being
used with positive voltage. The positive voltage may be used by a
conventional way, as being mentioned later, in which an electrode
coated with a polymer is employed as a working electrode in a
Cyclic Voltammetry.
[0070] The polymer of the present invention can be produced by
reacting one or more kinds of monomers selected from formula (3),
(4) and (5), and a compound of formula (6).
Y.sub.1--Ar.sub.1--Y.sub.2 (3) Y.sub.3--Ar.sub.2--Y.sub.4 (4)
Y.sub.5--Ar.sub.3--Y.sub.6 (5) E.sub.1-Y.sub.7 (6)
[0071] In the formula, Ar.sub.1, Ar.sub.2, and Ar.sub.3 each
independently represent an arylene group, divalent heterocyclic
group, or divalent aromatic amine group. E.sub.1 represents an
unsaturated hydrocarbon group free of aromatic ring. Y.sub.1,
Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5, and Y.sub.6 each independently
represent a leaving group, and Y.sub.7 represents a hydrogen atom
or a leaving group. Here, two or more kinds of compounds of (6)
also may be used.
[0072] Examples of the leaving groups include a halogen atom,
alkylsulfonyloxy group, arylsulfonyloxy group, or
--B(OR.sub.11).sub.2 (wherein, R.sub.11 is a hydrogen atom or alkyl
group); a halogen atom, alkylsulfonyloxy group and arylsulfonyloxy
group are preferable; and a halogen atom is further preferable.
[0073] As the halogen atom, chlorine atom, bromine atom, and iodine
atom are exemplified, chlorine atom and bromine atom are
preferable, and bromine atom is most preferable.
[0074] The alkylsulfonyloxy group may be substituted by fluorine
atom, and trifluoromethane sulfonyloxy group is exemplified.
[0075] The arylsulfonyloxy group may be substituted by alkyl group,
and phenylsulfonyloxy group, trisulfonyloxy group, etc. are
exemplified.
[0076] In the group represented by --B(OR.sub.11).sub.2, R.sub.11
is a hydrogen atom or alkyl group. The alkyl group has usually
about 1 to 20 carbon atoms, and includes a methyl group, ethyl
group, propyl group, butyl group, hexyl group, octyl group, dodecyl
group, etc. The alkyl groups themselves may form a ring bond.
[0077] Specifically, as the group represented by
--B(OR.sub.11).sub.2, following groups are exemplified.
##STR72##
[0078] Following groups are preferable. ##STR73##
[0079] When polymerization is carried out by using compounds
represented by formulas (3), (4), (5) and (6), if Y.sub.7 being a
leaving group, a compound represented by formula (6) is generally
charged in an amount of 0.1 to 10% by mole based on the total
amount of monomers represented by formulas (3), (4), (5) and (6),
preferably 0.2 to 5% by mole, or more preferably 0.5 to 3% by mole.
If Y.sub.7 being hydrogen atom, the compound represented by formula
(6) is generally charged in an amount of 10 to 1000% by mole based
on the total amount of monomers represented by formulas (3), (4)
and (5), preferably 50 to 500% by mole, or more preferably 100 to
300% by mole.
[0080] As the methods for producing the copolymer of the invention
by using the foregoing monomers, exemplified are a method of
polymerizztion according to Suzuki reaction (Chem. Rev. Vol. 95,
Page 2457 (1995)), a polymerization by Grignard Reaction (KYORITSU
SHUPPAN CO., LTD., Series of Functional Polymer Materials, Vol. 2,
Synthesis and Reaction of Polymers (2), Pages 432-433), a method of
polymerization according to Ymamoto polymerization reaction (Prog.
Polym. Sci., Vol. 17, Page 1153-1205 (1992)), a polymerization by
an oxidizing agent such as FeCl.sub.3 and the like, and a method of
oxidative polymerization by electrochemical way (MARUZEN Co,. Ltd.
Course of Chemical Experiments (4.sup.th version), Vol. 28 Pages
339-340).
[0081] The case employing Suzuki reaction is explained.
[0082] In this case, for example, with using monomers of which each
of Y.sub.1 and Y.sub.2 is independently a group represented by
--B(OR.sub.11).sub.2 (wherein R.sub.11 is hydrogen atom or alkyl
group); each of Y.sub.3 and Y.sub.4 is independently halogen atom,
alkylsulfonyloxy group or arylsulfonyloxy group; each of Y.sub.5
and Y.sub.6 is independently a group represented by
--B(OR.sub.11).sub.2 (wherein R.sub.11 is hydrogen atom or alkyl
group) or independently halogen atom, alkylsulfonyloxy group or
arylsulfonyloxy group; Y.sub.7 is a group represented by
--B(OR.sub.11).sub.2 (wherein R.sub.11 is hydrogen atom or alkyl
group); and Y.sub.8 is halogen atom, alkylsulfonyloxy group or
arylsulfonyloxy group; these monomers are subjected to reaction in
the presence of Pd(0) catalyst to produce a polymer.
[0083] In this case, of among two or more kinds of monomers having
two leaving groups which are subjected to the reaction, at least
one of them is a monomer having two --B(OR.sub.11).sub.2 (wherein
R.sub.1, is hydrogen atom or alkyl group,) and at least another one
of them is a monomer having two halogen atoms, alkylsulfonyloxy
groups or arylsulfonyloxy groups.
[0084] If Y.sub.7 is a leaving group, reaction is generally carried
out by subjecting monomers of (3) to (5) to reaction for about 1 to
100 hours, followed by the monomer (6) being added to the system to
react for about 0.5 to 50 hours. If Y.sub.7 is hydrogen atom,
reaction is generally carried out by subjecting monomers of (3) to
(6) to reaction for about 1 to 100 hours.
[0085] For the reaction, Pd(0) catalyst such as
palladium[tetrakis(triphenylphosphine)] or palladium acetates is
used with adding inorganic base such as potassium carbonate, sodium
carbonate and barium hydroxide, organic base such as triethylamine,
or inorganic salt such as cesium fluoride in an amount of
equivalent to monomers or more, or preferably 1 to 10 equivalent.
The inorganic salt may be used in aqueous state to carry out the
reaction in a two phase system. Solvent includes
N,N-dimethylformamide, toluene, dimethoxyethane and
tetrahydrofuran. The temperature in a range from 50 to 160.degree.
C. is suitably used depending on the solvent employed. The
temperature may be raised nearly up to the boiling point of the
solvent employed, and then refluxed. The reaction time is about 1
to 200 hours.
[0086] The case employing Yamamoto reaction is explained.
[0087] In this case, for example, with using monomers of which each
of Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5 and Y.sub.6 is
independently halogen atom, alkylsulfonyloxy group or
arylsulfonyloxy group, and Y.sub.7 is hydrogen atom, halogen atom,
alkylsulfonyloxy group or arylsulfonyloxy group, these monomers are
subjected to reaction in the presence of Ni(0) catalyst to produce
a polymer.
[0088] The reaction is generally carried out by mixing at least one
selected from the compounds (3) to (5) and at least one selected
from the compound (6).
[0089] Of the compound (6), preferable is a group of which Y.sub.7
is hydrogen atom and E.sub.1 contains two or more unsaturated bonds
in formula (6), more preferable is cyclooctadiene as a monomer of
formula (6), or further preferable is 1,5-cyclooctadiene.
[0090] 1,5-cyclooctadiene is generally charged in an amount of 10
to 1000% by mole based on the total amount of monomers represented
by formulas (3), (4) and (5), preferably 50 to 500% by mole, more
preferably 100 to 300% by mole, still more preferably 250 to 300%
by mole, or most preferably 260 to 275% by mole.
[0091] When using Ni(0) catalyst (zero-valent nickel complex) for
reaction, the possible way for preparing nickel complex is using
zero-valent nickel as itself or subjecting a salt of nickel to
reaction in the presence of a reduction agent to generate
zero-valent nickel in the reaction system.
[0092] The zero-valent nickel complex includes
bis(1,5-cyclooctadiene)nickel(0),
(ethylene)bis(triphenylphosphine)nickel(0),
tetrakis(triphenylphosphine)nickel and the like; of these,
bis(1,5-cyclooctadiene)nickel(0) is preferable due to its
versatility and inexpensive cost.
[0093] Addition of a neutral ligand is preferable in view of
enhancing yield.
[0094] The neutral ligand means a ligand not having anion or
cation, and examples thereof include a nitrogen-containing ligand
such as 2,2'-bipyridyl, 1,10-phenanthroline, methylenebisoxazoline
and N,N'-tetramethylethylenediamine; and tertiary phosphine ligand
such as triphenylphosphine, tritolylphosphine, tributylphosphine
and triphenoxyphosphine; of these, preferable is the
nitrogen-containing ligand due to its versatility and inexpensive
cost, or more preferable is 2,2'-bipyridyl in view of high
reactivity and high yield. Particularly preferable in view of
enhancing polymer yield is the system of a
bis(1,5-cyclooctadiene)nickel(0) containing system added with
2,2'-bipyridyl as a neutral ligand. Regarding a method of reacting
a zero-valent nickel in the reaction system, the nickel salt
includes nickel chloride, nickel acetate and the like. The reducing
agent includes zinc, sodium hydride and hydrazine and derivatives
thereof, and lithium aluminum hydride and the like; and additives
such as ammonium iodide, lithium iodide, potassium iodide and the
like may be used, if necessary.
[0095] The solvent for polymerization is not particularly limited
as far as not inhibiting the polymerization, preferable is the one
containing at least one kind of aromatic hydrocarbon solvents
and/or ether solvents.
[0096] The aromatic hydrocarbon solvents include, for example,
benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene,
butylbenzene, naphthalin and tetralin, or preferably toluene,
xylene, tetralin and tetramethylbenzene. The ether solvents
include, for example, diisopropyl ether, tetrahydrofuran,
1,4-dioxane, diphenyl ether, ethylene glycol dimethyl ether and
tert-butylmethyl ether, or preferably tetrahydrofuran and
1,4-dioxane which are good solvent for polymer compounds. Of
solvents, most preferable is tetrahydrofuran.
[0097] From a view point of improving polymerization property and
solubility, a solvent mixture composed of the aromatic hydrocarbon
solvent and/or the ether solvent being mixed with a solvent other
than the aromatic hydrocarbon solvent and ether solvent may be used
as far as not inhibiting the polymerization.
[0098] The reaction procedures may be carried out, for example,
according to the method described in JP-A No. 2000-44544.
[0099] In the Yamamoto polymerization method, the polymerization
reaction is generally carried out under an atmosphere of inert gas
such as argon and nitrogen in a tetrahydrofuran solvent at
60.degree. C. in the presence of a zero-valent nickel complex and a
neutral ligand. The polymerization time is usually about 0.5 to 100
hours, or preferably 10 hours or less due to saving production
cost; the polymerization temperature is usually about 0 to
200.degree. C., or preferably 20 to 100.degree. C. in view of high
yield and reducing heating cost.
[0100] When a neutral ligand is used, the amount used is, from view
points about reaction yields and production cost, preferably about
0.5 to 10 moles per 1 mole of the zero-valent nickel complex, more
preferably 0.8 to 1.5 moles, or still more preferably 0.9 to 1.1
moles.
[0101] The amount of the zero-valent nickel complex used is not
particularly limited as far as not disturbing polymerization
reaction; however, if the amount being too low, the molecular
weight tends to be decreased, and if the amount being too much,
post treatment tends to become troublesome; therefore, the amount
of 0.1 to 10 moles per 1 mole of monomer is preferable, 1 to 5
moles is more preferable, or 2 to 3.5 moles is still more
preferable.
[0102] When the polymer of the invention is employed as a light
emitting substance for polymer LEDs, since the purity thereof
affects to the light emitting property, it is preferable that
monomers provided for polymerization are purified in advance by the
ways such as distillation, sublimation or recrystallization, and
the polymer after being polymerized is subjected to purification
treatments such as reprecipitation purification or fractionation
with chromatography.
[0103] In the invention, for consideration regarding to
characteristics required to device formation such as solubility to
solvents, fluorescence intensity, life and brightness, two or more
polymers of the invention may be appropriately combined for
use.
[0104] The polymer of the invention is preferably used as a polymer
composition which is blended with a polymer emitting fluorescence
in the solid state and having a polystyrene-reduced number average
molecular weight of 10.sup.3 to 10.sup.8. The polymer to be blended
is not particularly limited as long as enhancing the
characteristics required to device formation such as solubility to
solvents, fluorescence intensity, life and brightness; specifically
included are the polymers disclosed in JP-A No. 2001-247861, JP-A
No. 2001-507511, JP-A No. 2001-504533, JP-A No. 2001-278958, JP-A
No. 2001-261796, JP-A No. 2001-226469, JP-B No. 3161058 and the
like, but not be limited thereto. The kind of the polymer compound
includes, for example, polyarylene type polymers such as
polyfluorene type polymers and polystilbene type polymers;
polyarylenevinylene type polymers; polystilbenevinylene type
polymers, polypyridinediyl type polymers and alkoxypolythiophene
type polymers. Of these, preferable is polyarylene based copolymers
(in which more preferable is polyfluorene type polymers or
polystilbene type polymers), polyarylenevinylene based copolymers
or polystilbenevinylene based copolymers. The amount of polymer
compound to be blended to enhance the foregoing characteristics is
preferably 5 to 60% by weight based on the total amount of the
polymer composition, more preferably 20 to 50% by weight, or most
preferably 25 to 35% by weight.
[0105] The polymer LED of the invention is characterized by having
a light emitting layer disposed between an anode electrode and a
cathode electrode, wherein the light emitting layer includes the
copolymer or the polymer composition of the invention.
[0106] The polymer LED of the invention also includes a polymer
light emitting device in which a layer having an electroconductive
polymer is disposed between at least one electrode and the light
emitting layer by being located adjacent to the electrode, and a
polymer light emitting device in which an insulating layer having
an average film thickness being 2 nm or less is disposed between at
least one electrode and the light emitting layer by being located
adjacent to the electrode.
[0107] As the polymer LED of the present invention, exemplified
are: a polymer LED having an electron transporting layer between a
cathode and a light emitting layer; a polymer LED having an hole
transporting layer between an anode and a light emitting layer; and
a polymer LED having an electron transporting layer between an
cathode and a light emitting layer, and a hole transporting layer
between an anode and a light emitting layer.
[0108] As the structure of polymer LED of the present invention,
the following structures a) to d) are specifically exemplified.
[0109] a) anode/light emitting layer/cathode
[0110] b) anode/hole transporting layer/light emitting
layer/cathode
[0111] c) anode/light emitting layer/electron transporting
layer/cathode
[0112] d) anode/hole transporting layer/light emitting
layer/electron transporting layer/cathode
[0113] (wherein, "/" indicates adjacent lamination of layers.
Hereinafter, the same).
[0114] Herein, the light emitting layer is a layer having function
to emit a light, the hole transporting layer is a layer having
function to transport a hole, and the electron transporting layer
is a layer having function to transport an electron. Herein, the
electron transporting layer and the hole transporting layer are
generically called a charge transporting layer.
[0115] The light emitting layer, hole transporting layer and
electron transporting layer also may be used each independently in
two or more layers.
[0116] Of charge transporting layers disposed adjacent to an
electrode, that having function to improve charge injecting
efficiency from the electrode and having effect to decrease driving
voltage of an device are particularly called sometimes a charge
injecting layer (hole injecting layer, electron injecting layer) in
general.
[0117] For enhancing adherence with an electrode and improving
charge injection from an electrode, the above-described charge
injecting layer or insulation layer having a thickness of 2 nm or
less may also be provided adjacent to an electrode, and further,
for enhancing adherence of the interface, preventing mixing and the
like, a thin buffer layer may also be inserted into the interface
of a charge transporting layer and light emitting layer.
[0118] The order and number of layers laminated and the thickness
of each layer can be appropriately used while considering light
emitting efficiency and life of the device.
[0119] In the present invention, as the polymer LED having a charge
injecting layer (electron injecting layer, hole injecting layer)
provided, there are listed a polymer LED having a charge injecting
layer provided adjacent to a cathode and a polymer LED having a
charge injecting layer provided adjacent to an anode.
[0120] For example, the following structures e) to p) are
specifically exemplified.
[0121] e) anode/charge injecting layer/light emitting
layer/cathode
[0122] f) anode/light emitting layer/charge injecting
layer/cathode
[0123] g) anode/charge injecting layer/light emitting layer/charge
injecting layer/cathode
[0124] h) anode/charge injecting layer/hole transporting
layer/light emitting layer/cathode
[0125] i) anode/hole transporting layer/light emitting layer/charge
injecting layer/cathode
[0126] j) anode/charge injecting layer/hole transporting
layer/light emitting layer/charge injecting layer/cathode
[0127] k) anode/charge injecting layer/light emitting
layer/electron transporting layer/cathode
[0128] l) anode/light emitting layer/electron transporting
layer/charge injecting layer/cathode
[0129] m) anode/charge injecting layer/light emitting
layer/electron transporting layer/charge injecting
layer/cathode
[0130] n) anode/charge injecting layer/hole transporting
layer/light emitting layer/electron transporting layer/cathode
[0131] o) anode/hole transporting layer/light emitting
layer/electron transporting layer/charge injecting
layer/cathode
[0132] p) anode/charge injecting layer/hole transporting
layer/light emitting layer/electron transporting layer/charge
injecting layer/cathode
[0133] As the specific examples of the charge injecting layer,
there are exemplified layers containing an conducting polymer,
layers which are disposed between an anode and a hole transporting
layer and contain a material having an ionization potential between
the ionization potential of an anode material and the ionization
potential of a hole transporting material contained in the hole
transporting layer, layers which are disposed between a cathode and
an electron transporting layer and contain a material having an
electron affinity between the electron affinity of a cathode
material and the electron affinity of an electron transporting
material contained in the electron transporting layer, and the
like.
[0134] When the above-described charge injecting layer is a layer
containing an conducting polymer, the electric conductivity of the
conducting polymer is preferably 10.sup.-5 S/cm or more and
10.sup.3 S/cm or less, and for decreasing the leak current between
light emitting pixels, more preferably 10.sup.-5 S/cm or more and
10.sup.2 S/cm or less, further preferably 10.sup.-5 S/cm or more
and 10.sup.1 S/cm or less.
[0135] Usually, to provide an electric conductivity of the
conducting polymer of 10.sup.-5 S/cm or more and 10.sup.3 S/cm or
less, a suitable amount of ions are doped into the conducting
polymer.
[0136] Regarding the kind of an ion doped, an anion is used in a
hole injecting layer and a cation is used in an electron injecting
layer. As examples of the anion, a polystyrene sulfonate ion,
alkylbenzene sulfonate ion, camphor sulfonate ion and the like are
exemplified, and as examples of the cation, a lithium ion, sodium
ion, potassium ion, tetrabutyl ammonium ion and the like are
exemplified.
[0137] The thickness of the charge injecting layer is for example,
from 1 nm to 100 nm, preferably from 2 nm to 50 nm.
[0138] Materials used in the charge injecting layer may properly be
selected in view of relation with the materials of electrode and
adjacent layers, and there are exemplified conducting polymers such
as polyaniline and derivatives thereof, polythiophene and
derivatives thereof, polypyrrole and derivatives thereof,
poly(phenylene vinylene) and derivatives thereof, poly(thienylene
vinylene) and derivatives thereof, polyquinoline and derivatives
thereof, polyquinoxaline and derivatives thereof, polymers
containing aromatic amine structures in the main chain or the side
chain, and the like, and metal phthalocyanine (copper
phthalocyanine and the like), carbon and the like.
[0139] The insulation layer having a thickness of 2 nm or less has
function to make charge injection easy. As the material of the
above-described insulation layer, metal fluoride, metal oxide,
organic insulation materials and the like are listed. As the
polymer LED having an insulation layer having a thickness of 2 nm
or less, there are listed polymer LEDs having an insulation layer
having a thickness of 2 nm or less provided adjacent to a cathode,
and polymer LEDs having an insulation layer having a thickness of 2
nm or less provided adjacent to an anode.
[0140] Specifically, there are listed the following structures q)
to ab) for example.
[0141] q) anode/insulation layer having a thickness of 2 nm or
less/light emitting layer/cathode
[0142] r) anode/light emitting layer/insulation layer having a
thickness of 2 nm or less/cathode
[0143] s) anode/insulation layer having a thickness of 2 nm or
less/light emitting layer/insulation layer having a thickness of 2
nm or less/cathode
[0144] t) anode/insulation layer having a thickness of 2 nm or
less/hole transporting layer/light emitting layer/cathode
[0145] u) anode/hole transporting layer/light emitting
layer/insulation layer having a thickness of 2 nm or
less/cathode
[0146] v) anode/insulation layer having a thickness of 2 nm or
less/hole transporting layer/light emitting layer/insulation layer
having a thickness of 2 nm or less/cathode
[0147] w) anode/insulation layer having a thickness of 2 nm or
less/light emitting layer/electron transporting layer/cathode
[0148] x) anode/light emitting layer/electron transporting
layer/insulation layer having a thickness of 2 nm or
less/cathode
[0149] y) anode/insulation layer having a thickness of 2 nm or
less/light emitting layer/electron transporting layer/insulation
layer having a thickness of 2 nm or less/cathode
[0150] z) anode/insulation layer having a thickness of 2 nm or
less/hole transporting layer/light emitting layer/electron
transporting layer/cathode
[0151] aa) anode/hole transporting layer/light emitting
layer/electron transporting layer/insulation layer having a
thickness of 2 nm or less/cathode
[0152] ab) anode/insulation layer having a thickness of 2 nm or
less/hole transporting layer/light emitting layer/electron
transporting layer/insulation layer having a thickness of 2 nm or
less/cathode
[0153] In the polymer LED of the present invention, light emitting
materials other than the above described polymer or polymer
composition can also be mixed in a light emitting layer. Further,
in the polymer LED of the present invention, the light emitting
layer containing light emitting materials other than the above
polymeric fluorescent substance may also be laminated with a light
emitting layer containing the above polymer.
[0154] As the light emitting material, known materials can be used.
In a compound having lower molecular weight, there can be used, for
example, naphthalene derivatives, anthracene or derivatives
thereof, perylene or derivatives thereof; dyes such as polymethine
dyes, xanthene dyes, coumarine dyes, cyanine dyes; metal complexes
of 8-hydroxyquinoline or derivatives thereof, aromatic amine,
tetraphenylcyclopentane or derivatives thereof, or
tetraphenylbutadiene or derivatives thereof, and the like.
[0155] Specifically, there can be used known compounds such as
those described in JP-A Nos. 57-51781, 59-195393 and the like, for
example.
[0156] Although the film molding of a light emitting layer is not
restricted, and for example, includes a method by film molding from
solution, for example.
[0157] As the film forming method from a solution, there can be
used coating methods such as a spin coating method, casting method,
micro gravure coating method, gravure coating method, bar coating
method, roll coating method, wire bar coating method, dip coating
method, spray coating method, screen printing method, flexo
printing method, offset printing method, inkjet printing method and
the like.
[0158] As the solvent used for film forming from a solution,
toluene, xylene, chloroform, and tetrahydrofuran are
exemplified.
[0159] Regarding the thickness of the light emitting layer, the
optimum value differs depending on material used, and may properly
be selected so that the driving voltage and the light emitting
efficiency become optimum values, and for example, it is from 1 nm
to 1 .mu.m, preferably from 2 nm to 500 nm, further preferably from
5 nm to 200 nm.
[0160] When the polymer LED of the present invention has a hole
transporting layer, as the hole transporting materials used, there
are exemplified polyvinylcarbazole or derivatives thereof,
polysilane or derivatives thereof, polysiloxane derivatives having
an aromatic amine in the side chain or the main chain, pyrazoline
derivatives, arylamine derivatives, stilbene derivatives,
triphenyldiamine derivatives, polyaniline or derivatives thereof,
polythiophene or derivatives thereof, polypyrrole or derivatives
thereof, poly(p-phenylenevinylene) or derivatives thereof,
poly(2,5-thienylenevinylene) or derivatives thereof, or the
like.
[0161] Specific examples of the hole transporting material include
those described in JP-A Nos. 63-70257, 63-175860, 2-135359,
2-135361, 2-209988, 3-37992 and 3-152184.
[0162] Among them, as the hole transporting materials used in the
hole transporting layer, preferable are polymer hole transporting
materials such as polyvinylcarbazole or derivatives thereof,
polysilane or derivatives thereof, polysiloxane derivatives having
an aromatic amine compound group in the side chain or the main
chain, polyaniline or derivatives thereof, polythiophene or
derivatives thereof, poly(p-phenylenevinylene) or derivatives
thereof, poly(2,5-thienylenevinylene) or derivatives thereof, or
the like, and further preferable are polyvinylcarbazole or
derivatives thereof, polysilane or derivatives thereof and
polysiloxane derivatives having an aromatic amine compound group in
the side chain or the main chain. In the case of a hole
transporting material having lower molecular weight, it is
preferably dispersed in a polymer binder for use.
[0163] Polyvinylcarbazole or derivatives thereof are obtained, for
example, by cation polymerization or radical polymerization from a
vinyl monomer.
[0164] As the polysilane or derivatives thereof, there are
exemplified compounds described in Chem. Rev., 89, 1359 (1989) and
GB 2300196 published specification, and the like. For synthesis,
methods described in them can be used, and a Kipping method can be
suitably used particularly.
[0165] As the polysiloxane or derivatives thereof, those having the
structure of the above-described hole transporting material having
lower molecular weight in the side chain or main chain, since the
siloxane skeleton structure has poor hole transporting property.
Particularly, there are exemplified those having an aromatic amine
having hole transporting property in the side chain or main
chain.
[0166] The method for forming a hole transporting layer is not
restricted, and in the case of a hole transporting layer having
lower molecular weight, a method in which the layer is formed from
a mixed solution with a polymer binder is exemplified. In the case
of a polymer hole transporting material, a method in which the
layer is formed from a solution is exemplified.
[0167] The solvent used for the film forming from a solution is not
particularly restricted providing it can dissolve a hole
transporting material. As the solvent, there are exemplified
chlorine solvents such as chloroform, methylene chloride,
dichloroethane and the like, ether solvents such as tetrahydrofuran
and the like, aromatic hydrocarbon solvents such as toluene, xylene
and the like, ketone solvents such as acetone, methyl ethyl ketone
and the like, and ester solvents such as ethyl acetate, butyl
acetate, ethylcellosolve acetate and the like.
[0168] As the film forming method from a solution, there can be
used coating methods such as a spin coating method, casting method,
micro gravure coating method, gravure coating method, bar coating
method, roll coating method, wire bar coating method, dip coating
method, spray coating method, screen printing method, flexo
printing method, offset printing method, inkjet printing method and
the like, from a solution.
[0169] The polymer binder mixed is preferably that does not disturb
charge transport extremely, and that does not have strong
absorption of a visible light is suitably used. As such polymer
binder, polycarbonate, polyacrylate, poly(methyl acrylate),
poly(methyl methacrylate), polystyrene, poly(vinyl chloride),
polysiloxane and the like are exemplified.
[0170] Regarding the thickness of the hole transporting layer, the
optimum value differs depending on material used, and may properly
be selected so that the driving voltage and the light emitting
efficiency become optimum values, and at least a thickness at which
no pin hole is produced is necessary, and too large thickness is
not preferable since the driving voltage of the device increases.
Therefore, the thickness of the hole transporting layer is, for
example, from 1 nm to 1 .mu.m, preferably from 2 nm to 500 nm,
further preferably from 5 nm to 200 nm.
[0171] When the polymer LED of the present invention has an
electron transporting layer, known compounds are used as the
electron transporting materials, and there are exemplified
oxadiazole derivatives, anthraquinonedimethane or derivatives
thereof, benzoquinone or derivatives thereof, naphthoquinone or
derivatives thereof, anthraquinone or derivatives thereof,
tetracyanoanthraquinodimethane or derivatives thereof, fluorenone
derivatives, diphenyldicyanoethylene or derivatives thereof,
diphenoquinone derivatives, or metal complexes of
8-hydroxyquinoline or derivatives thereof, polyquinoline and
derivatives thereof, polyquinoxaline and derivatives thereof,
polyfluorene or derivatives thereof, and the like.
[0172] Specifically, there are exemplified those described in JP-A
Nos. 63-70257, 63-175860, 2-135359, 2-135361, 2-209988, 3-37992 and
3-152184.
[0173] Among them, oxadiazole derivatives, benzoquinone or
derivatives thereof, anthraquinone or derivatives thereof, or metal
complexes of 8-hydroxyquinoline or derivatives thereof,
polyquinoline and derivatives thereof, polyquinoxaline and
derivatives thereof, polyfluorene or derivatives thereof are
preferable, and
2-(4-biphenyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole, benzoquinone,
anthraquinone, tris(8-quinolinol)aluminum and polyquinoline are
further preferable.
[0174] The method for forming the electron transporting layer is
not particularly restricted, and in the case of an electron
transporting material having lower molecular weight, a vapor
deposition method from a powder, or a method of film-forming from a
solution or melted state is exemplified, and in the case of a
polymer electron transporting material, a method of film-forming
from a solution or melted state is exemplified, respectively.
[0175] The solvent used in the film-forming from a solution is not
particularly restricted provided it can dissolve electron
transporting materials and/or polymer binders. As the solvent,
there are exemplified chlorine solvents such as chloroform,
methylene chloride, dichloroethane and the like, ether solvents
such as tetrahydrofuran and the like, aromatic hydrocarbon solvents
such as toluene, xylene and the like, ketone solvents such as
acetone, methyl ethyl ketone and the like, and ester solvents such
as ethyl acetate, butyl acetate, ethylcellosolve acetate and the
like.
[0176] As the film-forming method from a solution or melted state,
there can be used coating methods such as a spin coating method,
casting method, micro gravure coating method, gravure coating
method, bar coating method, roll coating method, wire bar coating
method, dip coating method, spray coating method, screen printing
method, flexo printing method, offset printing method, inkjet
printing method and the like.
[0177] The polymer binder to be mixed is preferably that which does
not extremely disturb a charge transport property, and that does
not have strong absorption of a visible light is suitably used. As
such polymer binder, poly(N-vinylcarbazole), polyaniline or
derivatives thereof, polythiophene or derivatives thereof,
poly(p-phenylene vinylene) or derivatives thereof,
poly(2,5-thienylene vinylene) or derivatives thereof,
polycarbonate, polyacrylate, poly(methyl acrylate), poly(methyl
methacrylate), polystyrene, poly(vinyl chloride), polysiloxane and
the like are exemplified.
[0178] Regarding the thickness of the electron transporting layer,
the optimum value differs depending on material used, and may
properly be selected so that the driving voltage and the light
emitting efficiency become optimum values, and at least a thickness
at which no pin hole is produced is necessary, and too large
thickness is not preferable since the driving voltage of the device
increases. Therefore, the thickness of the electron transporting
layer is, for example, from 1 nm to 1 .mu.m, preferably from 2 nm
to 500 nm, further preferably from 5 nm to 200 nm.
[0179] The substrate forming the polymer LED of the present
invention may preferably be that does not change in forming an
electrode and layers of organic materials, and there are
exemplified glass, plastics, polymer film, silicon substrates and
the like. In the case of a opaque substrate, it is preferable that
the opposite electrode is transparent or semitransparent.
[0180] Usuallu, at least one of the electrodes consisting of an
anode and a cathode, is transparent or semitransparent. It is
preferable that the anode is transparent or semitransparent. As the
material of this anode, electron conductive metal oxide films,
semitransparent metal thin films and the like are used.
Specifically, there are used indium oxide, zinc oxide, tin oxide,
and films (NESA and the like) fabricated by using an electron
conductive glass composed of indium/tin/oxide (ITO),
indium/zinc/oxide and the like, which are metal oxide complexes,
and gold, platinum, silver, copper and the like are used, and among
them, ITO, indium/zinc/oxide, tin oxide are preferable. As the
fabricating method, a vacuum vapor deposition method, sputtering
method, ion plating method, plating method and the like are used.
As the anode, there may also be used organic transparent conducting
films such as polyaniline or derivatives thereof, polythiophene or
derivatives thereof and the like.
[0181] The thickness of the anode can be appropriately selected
while considering transmission of a light and electric
conductivity, and for example, from 10 nm to 10 .mu.m, preferably
from 20 nm to 1 .mu.m, further preferably from 50 nm to 500 nm.
[0182] Further, for easy charge injection, there may be provided on
the anode a layer comprising a phthalocyanine derivative conducting
polymers, carbon and the like, or a layer having an average film
thickness of 2 nm or less comprising a metal oxide, metal fluoride,
organic insulating material and the like.
[0183] As the material of a cathode used in the polymer LED of the
present invention, that having lower work function is preferable.
For example, there are used metals such as lithium, sodium,
potassium, rubidium, cesium, beryllium, magnesium, calcium,
strontium, barium, aluminum, scandium, vanadium, zinc, yttrium,
indium, cerium, samarium, europium, terbium, ytterbium and the
like, or alloys comprising two of more of them, or alloys
comprising one or more of them with one or more of gold, silver,
platinum, copper, manganese, titanium, cobalt, nickel, tungsten and
tin, graphite or graphite intercalation compounds and the like.
Examples of alloys include a magnesium-silver alloy,
magnesium-indium alloy, magnesium-aluminum alloy, indium-silver
alloy, lithium-aluminum alloy, lithium-magnesium alloy,
lithium-indium alloy, calcium-aluminum alloy and the like. The
cathode may be formed into a laminated structure of two or more
layers.
[0184] The thickness of the cathode can be appropriately selected
while considering transmission of a light and electric
conductivity, and for example, from 10 nm to 10 .mu.m, preferably
from 20 nm to 1 .mu.m, further preferably from 50 nm to 500 nm.
[0185] As the method for fabricating a cathode, there are used a
vacuum vapor deposition method, sputtering method, lamination
method in which a metal thin film is adhered under heat and
pressure, and the like. Further, there may also be provided,
between a cathode and an organic layer, a layer comprising an
conducting polymer, or a layer having an average film thickness of
2 nm or less comprising a metal oxide, metal fluoride, organic
insulation material and the like, and after fabrication of the
cathode, a protective layer may also be provided which protects the
polymer LED. For stable use of the polymer LED for a long period of
time, it is preferable to provide a protective layer and/or
protective cover for protection of the device in order to prevent
it from outside damage.
[0186] As the protective layer, there can be used a polymeric
compound, metal oxide, metal fluoride, metal borate and the like.
As the protective cover, there can be used a glass plate, a plastic
plate the surface of which has been subjected to
lower-water-permeation treatment, and the like, and there is
suitably used a method in which the cover is pasted with an device
substrate by a thermosetting resin or light-curing resin for
sealing. If space is maintained using a spacer, it is easy to
prevent an device from being injured. If an inner gas such as
nitrogen and argon is sealed in this space, it is possible to
prevent oxidation of a cathode, and further, by placing a desiccant
such as barium oxide and the like in the above-described space, it
is easy to suppress the damage of an device by moisture adhered in
the production process. Among them, any one means or more are
preferably adopted.
[0187] The polymer LED of the present invention can be used for a
flat light source, a segment display, a dot matrix display, and a
liquid crystal display as a back light, etc.
[0188] For obtaining light emission in plane form using the polymer
LED of the present invention, an anode and a cathode in the plane
form may properly be placed so that they are laminated each other.
Further, for obtaining light emission in pattern form, there is a
method in which a mask with a window in pattern form is placed on
the above-described plane light emitting device, a method in which
an organic layer in non-light emission part is formed to obtain
extremely large thickness providing substantial non-light emission,
and a method in which any one of an anode or a cathode, or both of
them are formed in the pattern. By forming a pattern by any of
these methods and by placing some electrodes so that independent
on/off is possible, there is obtained a display device of segment
type which can display digits, letters, simple marks and the like.
Further, for forming a dot matrix device, it may be advantageous
that anodes and cathodes are made in the form of stripes and placed
so that they cross at right angles. By a method in which a
plurality of kinds of polymeric compounds emitting different colors
of lights are placed separately or a method in which a color filter
or luminescence converting filter is used, area color displays and
multi color displays are obtained. A dot matrix display can be
driven by passive driving, or by active driving combined with TFT
and the like. These display devices can be used as a display of a
computer, television, portable terminal, portable telephone, car
navigation, view finder of a video camera, and the like.
[0189] Further, the above-described light emitting device in plane
form is a thin self-light-emitting one, and can be suitably used as
a flat light source for back-light of a liquid crystal display, or
as a flat light source for illumination. Further, if a flexible
plate is used, it can also be used as a curved light source or a
display.
[0190] The invention is explained in more detail hereinafter by
referring to examples, but not be limited thereto.
[0191] The polystyrene-reduced number average molecular weight and
weight average molecular weight were obtained by a gel permeation
chromatography (GPC). Chloroform was used as a solvent, and a
differential refractive index detector was applied for
detection.
[0192] The structure of the polymer ends was analyzed by a mass
spectrometry method using a time-of-flight mass spectrometry
equipped with matrix assisted laser desorption ionization device
(referred to as MALDI-TOFMS hereinafter) and a solution
high-resolution nuclear magnetic resonance method (being referred
to as high-resolution NMR method hereinafter) according to the
following procedures; a matrix solution for MALDI and a
tetrahydrofuran solution of a polymer was mixed in a ratio of 5:1
by volume, 1 .mu.l of the mixture was put on a target plate, and
then being inserted into the MALDI-TOFMS Reflex III type
manufactured by BRUKER DALLTONICS to be measured in positive
ionization mode. The mass numbers resulting from the measurement
were analyzed to calculating out a exact mass number of the
individual polymer, followed by the polymerization degree and the
functional group coupling with terminal ends were specified.
[0193] The presence of unsaturated bond excluding aromatic ring was
further evaluated according to NMR spectrum of a polymer obtained
by subjecting the polymer dissolved in deuterium-labeled chloroform
to measurement by a high-resolution NMR, the evaluation was
performed according to the presence of peaks appeared in the
chemical shift ranging from 5.5 to 6.0 ppm under TMS being set at 0
ppm.
[0194] The test for resistibility to electrolytic reduction was
carried out by following procedures; 1% toluene solution of a
polymer was coated by spinning on a gold electrode evaporated on
the glass plate, followed by being dried under ambient atmosphere
and then further being dried at 60.degree. C. under a reduced
pressure to prepare a working electrode; the prepared working
electrode, a platinum electrode as counter electrode, a non-aqueous
Ag/Ag.sup.+ reference electrode as reference electrode and a 0.1 M
dehydrated acetonitrile solution of tetra-n-butylammonium
tetrafluoroborate as electrolyte were used for the test; and the
working electrode, the counter electrode and the reference
electrode were immersed into the electrolyte in a gloved box, each
of electrode was respectively connected to an
electrochemical-analyzer model 600A manufactured by ALS Company,
and then the working electrode was retained for 90 minutes by being
applied with the voltage of -2.6 V. After the voltage was return to
0 V, the surface of working electrode was washed with dehydrated
acetonitrile, followed by the polymer on the working electrode
surface being dissolved with toluene to obtain a toluene solution
of the polymer. This toluene solution and a toluene solution of the
polymer before voltage application were independently analyzed by
GPC, followed by a molecular weight at the peak position appeared
in the respective GPC chromatogram being set for the
polystyrene-reduced molecular weight of the polymer (being referred
to as M.sub.p hereinafter). The detection of GPC was carried out by
an ultra-violet detector. Then M.sub.p values respectively measured
were applied to obtain a scale to evaluate resistibility to
electrolytic reduction, the scaling value was calculated as
follows; an amount of the difference between M.sub.p after voltage
application and M.sub.p before voltage application is divided by
M.sub.p before voltage application (this value being referred to as
.DELTA.M.sub.p/M.sub.p hereinafter). If .DELTA.M.sub.p/M.sub.p
shows negative value, this means average molecular weight being
decreased by the electrolytic reduction treatment; consequently
resistibility to electrolytic reduction is low. On the other hand,
if .DELTA.M.sub.p/M.sub.p shows 0 or positive value, this means
average molecular weight being unchanged or increased by the
electrolytic reduction treatment; consequently resistibility to
electrolytic reduction is high.
EXAMPLE 1
<Synthesis of Polymer 1>
[0195] 2,7-dibromo-9,9-dioctylfluorene (450 mg, 0.82 mmol),
2,7-dibromo-9,9-diisopentylfluorene (130 mg, 0.27 mmol),
1,5-cyclooctadiene (310 mg, 2.9 mmol) and 2,2'-bipyridyl (320 mg,
2.1 mmol) were dissolved in 28 mL of dehydrated tetrahydrofuran,
followed by the solution being bubbled with nitrogen to replace
inside of the system with nitrogen. Bis(1,5-cyclooctadiene)nickel
(0){Ni(COD).sub.2}(580 mg, 2.1 mmol) was added into the solution
under nitrogen atmosphere, followed by being heated up to
60.degree. C. and reacted for 3 hours with being stirred. After the
reaction finished, the reactant was cooled down to the room
temperature (about 25.degree. C.), followed by being dropped into a
mixture of 10 mL of 25% aqueous ammonia/120 mL of methanol/50 mL of
ion-exchange water and being stirred for 1 hour to precipitate, and
then the precipitate was filtered, followed by being dried for 2
hours under reduced pressure and then being dissolved in 30 mL of
toluene. The toluene solution was added with 30 mL of 1 N
hydrochloric acid, followed by being stirred for 1 hour, the
organic layer obtained after the aqueous layer being removed from
the solution was added with 30 mL of 4% aqueous ammonia, followed
by being stirred for 1 hour and then the aqueous layer being
removed. The organic layer was dropped into 200 mL of methanol,
followed by being stirred for 1 hour to precipitate, and then the
precipitate was filtered, followed by being dried for 2 hours under
reduced pressure and then being dissolved in 30 mL of toluene. The
toluene solution was purified by passing through a column packed
with alumina (amount of alumina being 20 g), then the recovered
toluene solution was dropped into 150 mL of methanol, followed by
being stirred for 1 hour to precipitate, and then the precipitate
was filtered, followed by being dried for 2 hours under reduced
pressure. The amount of Polymer 1 obtained was 250 mg. The ratio of
the repeating unit of formula (8) to that of formula (9) in Polymer
1 was 75:25 according to the ratio of monomers charged for
reaction. ##STR74##
[0196] The polystyrene-reduced number average molecular weight of
Polymer 1 was 1.5.times.10.sup.4, and the polystyrene-reduced
weight average molecular weight thereof was 3.2.times.10.sup.4.
<Analysis of Terminal Ends of Polymer 1>
[0197] Resulting from the analysis of MALDI-TOFMS spectrum of
Polymer 1, molecules having mass number exhibited in Table 1 were
observed; detected were a peak having mass number greater in the
extent of 1,5-cyclooctadiene's molecular weight (108)-2 in
comparison with the mass number having hydrogen-substituted
terminal end groups at the both terminal ends, and a molecule
having mass number greater in the extent of twice of
1,5-cyclooctadiene's molecular weight (216)-4 in comparison with
the foregoing way. According to this result, analyzed were two
kinds of polymer; the polymer chain of which one end was coupled
with a group derived from 1,5-cyclooctadiene, i.e.
C.sub.8H.sub.11-- group, and the other end was hydrogen-substituted
terminal end group, and the polymer chain of which both ends were
coupled with C.sub.8H.sub.11-- group. The C.sub.8H.sub.11-- group
is a group derived from formula (2) by setting i=8 and j=2. In
addition, since the presence of a peak was observed in the range
from 5.5 to 6.0 ppm in high-resolution NMR spectrum of Polymer 1,
it is found that C.sub.8H.sub.11-- group existing at terminal end
of Polymer 1 had an unsaturated bond excluding aromatic ring.
TABLE-US-00001 TABLE 1 Results of MALDI-TOFMS on Polymer 1 Terminal
Mass End Number M N Group 1295.02 2 1 E-, E- 1379.11 3 0 E-, E-
1515.14 1 3 E-, E- 1577.25 3 1 H-, E- 1599.24 2 2 E-, E- 1661.35 4
0 H-, E- 1683.33 3 1 E-, E- 1767.42 4 0 E-, E- 1881.47 3 2 H-, E-
1903.46 2 3 E-, E- 1965.57 4 1 H-, E- 1987.55 3 2 E-, E- 2049.66 5
0 H-, E- 2071.64 4 1 E-, E- 2155.74 5 0 E-, E- 2207.67 2 4 E-, E-
2269.78 4 2 H-, E- 2291.77 3 3 E-, E- 2353.88 5 1 H-, E- 2375.86 4
2 E-, E- 2437.97 6 0 H-, E- 2459.96 5 1 E-, E- 2544.05 6 0 E-, E-
2574.00 4 3 H-, E- 2595.99 3 4 E-, E- 2658.10 5 2 H-, E- 2680.08 4
3 E-, E- 2742.19 6 1 H-, E- 2764.18 5 2 E-, E- 2826.28 7 0 H-, E-
2848.27 6 1 E-, E- 2932.36 7 0 E-, E- 2962.32 5 3 H-, E- 2984.30 4
4 E-, E- 3046.41 6 2 H-, E- 3068.39 5 3 E-, E- 3130.50 7 1 H-, E-
3152.49 6 2 E-, E- 3214.60 8 0 H-, E- 3236.58 7 1 E-, E- 3320.68 8
0 E-, E- 3350.63 6 3 H-, E- 3372.61 5 4 E-, E- 3434.72 7 2 H-, E-
3456.71 6 3 E-, E- 3518.82 8 1 H-, E- 3540.80 7 2 E-, E- 3602.91 9
0 H-, E- 3624.90 8 1 E-, E- 3708.99 9 0 E-, E- 3738.94 7 3 H-, E-
3760.93 6 4 E-, E- 3823.04 8 2 H-, E- 3845.02 7 3 E-, E- 3907.13 9
1 H-, E- 3929.11 8 2 E-, E- 4013.21 9 1 E-, E- 4097.30 10 0 E-,
E-
[0198] Since each atom has some kinds of stable isotopes, a
compound is observed in the MALDI-TOFMS spectrum as a set of plural
peaks split depending on the presence probability of the stable
isotopes. Listed in Table 1 is a typical mass number peak of plural
peaks observed in the MALDI-TOFMS spectrum, the typical mass number
peak means a peak solely composed of an atom having smallest mass
number selected from the stable isotopes thereof, that is, .sup.1H
in hydrogen, .sup.12C in carbon atom, .sup.14N in nitrogen and
.sup.16O in oxygen. A sign of M in Table represents the number of
9,9-dioctylfluorene repeating unit composing the polymer, and a
sign of N represents the number of 9,9-diisopentylfluorene
repeating unit composing the polymer. A sign of .left
brkt-top.H.sup.-.right brkt-bot. described in the terminal end
group column shows a terminal end group being the foregoing
hydrogen-substituted terminal end group, and a sign of .left
brkt-top.E.sup.-.right brkt-bot. shows a terminal end group of
molecular chain being C.sub.8H.sub.11-- group. Judging from the
observed peaks, it is clear that no repeating unit other than
9,9-dioctylfluorene repeating unit and 9,9-diisopentylfluorene
repeating unit are contained in Polymer 1. Consequently, the
C.sub.8H.sub.11-- group as the terminal end group of the molecular
chain directly couples with 9,9-dioctylfluorene repeating unit or
9,9-diisopentylfluorene repeating unit.
<Resistibility Test to Electrolytic Reduction of Polymer
1>
[0199] Since .DELTA.M.sub.p/M.sub.p of Polymer 1 obtained by the
foregoing method was a positive value of +0.026, the resistibility
to electrolytic reduction of Polymer 1 was excellent.
SYNTHESIS EXAMPLE 1
<Synthesis of Polymer 2>
[0200] Under nitrogen atmosphere,
9,9-dioctylfluorene-2,7-bis(ethyleneboronate) (305 mg, 0.575 mmol),
2,7-dibromo-9,9-diisopentylfluorene (309 mg, 0.564 mmol), and
aliquat 336 (16 mg, 0.040 mmol) were dissolved in toluene (4.3 g),
followed by the solution being added with 1.0 g of aqueous
potassium carbonate (249 mg, 1.80 mmol). The solution was further
added with tetrakis(triphenylphosphine)palladium (4 mg, 0.0036
mmol), followed by being heated up to 110.degree. C. and reacted
for 20 hours with being stirred. After the reaction finished, the
reactant was added with a solution of bromobenzene (14 mg, 0.0892
mmol) dissolved in 0.1 mL of toluene, followed by being stirred at
110.degree. C. for 5 hours. After the reactant was cooled down to
50.degree. C., the organic layer thereof was dropped into a mixture
of methanol/water (1/1) and being stirred for 1 hour to
precipitate. The precipitate was filtered, followed by being washed
with methanol and ion-exchange water and then being dried under
reduced pressure. This dried substance was dissolved in 50 mL of
toluene, followed by the toluene solution being purified by passing
through a column packed with silica (silica volume being 15 mL).
The purified solution was dropped into methanol, followed by being
stirred for 1 hour to precipitate, and then the precipitate was
filtered, followed by being dried under reduced pressure to obtain
Polymer 2. The amount of Polymer 2 obtained was 370 mg.
[0201] The polystyrene-reduced number average molecular weight of
Polymer 2 was 2.8.times.10.sup.4, and the polystyrene-reduced
weight average molecular weight thereof was 7.9.times.10.sup.4.
COMPARATIVE EXAMPLE 1
<Analysis of Terminal Ends of Polymer 2>
[0202] Resulting from the analysis of MALDI-TOFMS spectrum of
Polymer 2, molecules having mass number exhibited in Table 2 were
observed; detected were a molecule having mass number having
hydrogen-substituted terminal end groups at the both terminal ends,
as well as a peak having mass number greater in the extent of
phenylene group's formula weight (72) in comparison with the mass
number having hydrogen-substituted terminal end group at the both
terminal ends, and a molecule having mass number greater in the
extent of twice of phenylene group's formula weight phenylene
group's formula weight (152) in comparison with the foregoing way.
According to this result, Polymer 2 was analyzed as a mixture of
the polymer having hydrogen-substituted terminal end groups at the
both terminal ends thereof, the polymer having phenyl group at one
terminal end thereof and hydrogen-substituted terminal end group at
another terminal end thereof, and the polymer having phenyl groups
at both terminal ends thereof. In addition, since no peak was
observed in the range from 5.5 to 6.0 ppm in high resolution NMR
spectrum of Polymer 2, it is found that no unsaturated bond
excluding aromatic ring exist at the terminal end of Polymer 2.
TABLE-US-00002 TABLE 2 Results of MALDI-TOFMS on Polymer 2 Mass
Terminal End Number N Group 1166.95 3 H-, H- 1242.99 3 H-, Phenyl
group 1319.02 3 Phenyl group, Phenyl group 1555.27 4 H-, H- 1631.30
4 H-, Phenyl group 1943.58 5 H-, H- 2019.61 5 H-, Phenyl group
2095.64 5 Phenyl group, Phenyl group 2331.89 6 H-, H- 2407.92 6 H-,
Phenyl group 2720.21 7 H-, H- 2796.24 7 H-, Phenyl group 2872.27 7
Phenyl group, Phenyl group 3108.52 8 H-, H- 3184.55 8 H-, Phenyl
group 3496.83 9 H-, H- 3572.86 9 H-, Phenyl group 3648.90 9 Phenyl
group, Phenyl group 3885.15 10 H-, H- 3961.18 10 H-, Phenyl group
4273.46 11 H-, H- 4349.49 11 H-, Phenyl group 4425.52 11 Phenyl
group, Phenyl group
[0203] Since each atom has some kinds of stable isotopes, a
compound is observed in the MALDI-TOFMS spectrum as a set of plural
peaks split depending on the presence probability of the stable
isotopes. Listed in Table is a typical mass number peak of plural
peaks observed in the MALDI-TOFMS spectrum, the typical mass number
peak means a peak solely composed of an atom having smallest mass
number selected from the stable isotopes thereof, that is, .sup.1H
in hydrogen, .sup.12C in carbon atom, .sup.14N in nitrogen and
.sup.16O in oxygen. A sign of N in Table represents the number of
9,9-diisopentylfluorene repeating unit composing the polymer. A
sign of .left brkt-top.H.sup.-.right brkt-bot. described in the
terminal end group column shows a terminal end group being the
foregoing hydrogen-substituted terminal end group, and a sign of
.left brkt-top.Phenyl group.right brkt-bot. shows a terminal end
group of molecular chain being phenyl group.
<Resistibility Test to Electrolytic Reduction of Polymer
2>
[0204] Since .DELTA.M.sub.p/M.sub.p of Polymer 2 obtained by the
foregoing method was a negative value of -0.051, the resistibility
to electrolytic reduction of Polymer 2 was low.
[0205] A polymer of the invention is resistible to electrolytic
oxidation and/or reduction, particularly to electrolytic reduction
which seem to be frequently developed by the electric current
supplied. A polymer LED employing the polymer is suitably used for
curved or flat light sources used for a backlight of liquid crystal
display or lighting, segment display, dot matrix flat panel display
and the like. A coploymer of the invention is available for dyes
for laser, materials for organic solar battery, organic
semiconductors of organic transistor and materials for
electroconductive thin film.
* * * * *